1. Field of the Invention
The present invention relates to networking systems, and, more particularly, to wireless networking systems.
2. Description of the Related Art
Wireless sensor networks provide efficient solutions for many new or existing applications in building technology, industry, and the military. Security systems for intrusion detection, fire alarm systems, HVAC climate control systems, and environmental monitoring systems are some of the practical applications of wireless sensor networks.
The main motivations for the use of wireless sensor networks are to reduce the installation and maintenance costs, increase deployment flexibility, and enable the installation process to be as unobtrusive as possible. The advent of wireless solutions has been fueled by advances in low cost and low power radio transceivers as most envisioned systems are battery operated and expected to be successful only if they are low in cost.
In wireless sensor networks, periodic data collection or node supervision is utilized in many applications. During the data collection process, messages from the wireless nodes in the network are periodically collected and sent back to a central controller, such as a base station, for further processing. The content of the messages may be sensor readings or any other low-priority data, for example. Node supervision, which is especially important in security systems, is the process of periodic functional checks of every node in the network. Thus, in the node supervision process, the content of the messages may be acknowledgements from the sensor nodes indicating that all nodes are still operating.
Wireless systems pose a new set of protocol design challenges as the network's useful lifetime before failure and the network's reliability become two important design factors. The sensor nodes in the system are typically small and battery-operated, and are required to live for years before failure. Therefore, energy-efficiency is a crucial factor in all the tasks performed throughout the network's lifetime. Ensuring reliability is an important element of a wireless system, since wireless as a physical medium of communication is more prone to errors than its wired counterpart.
A particular problem with battery-operated wireless systems is that one node may be utilized to a greater extent than the other nodes. Thus, the node that is utilized to a greater extent may exhaust its battery power and fail prematurely, thereby reducing the useful lifetime of the entire system before service is required.
What is neither disclosed nor suggested by the prior art is an arrangement for a wireless network that evens out the battery usage among the various nodes, thereby increasing the useful lifetime of the entire system before service is required.